Conventional holographic video storage equipment includes (i) a laser beam source, (ii) a beam splitter, (iii) a spatial light modulator, and (iv) a flat, transparent, holographic storage disk. To write data to the disk, the laser beam source emits a beam of laser light. The beam splitter separates the laser beam into a signal beam and a reference beam. The spatial light modulator encodes a data pattern within the signal beam but not into the reference beam. The signal beam and the reference beam then intersect each other at a relatively-narrow location of the holographic storage disk. Photosensitive material within the holographic storage disk reacts to the intersection of these beams and, as a result, stores the data pattern three-dimensionally as layered digital pages (i.e., a hologram) at that location.
In contrast to conventional compact disks (CDs) and digital versatile disks (DVDs) which are flat, reflective disks that reflect laser light from a laser source onto an optical reader while the disks are spinning, a flat, transparent, holographic storage disk remains stationary during the writing and reading process. Furthermore, the holographic storage disk is mainly non-reflective so that, during the reading process, light from one side of the holographic storage disk shines on a hologram within the disk (i.e., layered digital pages) and a sensor on the other side of the disk reads the refracted light to re-construct the data pattern.
Since the data pattern is capable of including several digital pages of data, a significant amount of information can be stored on a single holographic storage disk. Some companies have reported the capability of storing 2 Gigabytes (GBs) in an area of a holographic storage disk which is roughly the size of a conventional postage stamp, as well as the ability to read that data at a rate of 20 Megabits per second (Mb/s). An example of a company providing similar reports is InPhase Technologies of Longmont, Colo.